This invention relates to combined systems for supplying both distilled water such as may be used for drinking purposes and hot water such as may be used for domestic purposes such as showers and baths and the like.
In one class of prior art combined distilling and hot water systems, there is a holding tank for the distilled water, an evaporator tank for vaporizing the water and a condenser which communicates between the two to condense the evaporated water into a purified distillate. It has been suggested that the heat removed from the condenser to condense the distillate may be used for heating water.
In one prior art distilling apparatus of this class, the water which receives heat from the condenser is discarded and only the distilled water is used, both as a supply of hot water and as pure water. This type of system is disclosed in U.S. Pat. No. 2,217,266.
Moreover, in the literature relating to this type of apparatuses for distilling water, there have been suggestions that the heat from stills for drinking water be used to supply hot water as well. These prior art disclosures have not suggested how this might be done economically or beneficially and have not disclosed some of the problems associated with such systems.
Three of the problems, for example, are: (1) the difficulty of economically balancing the amount of hot water with the amount of distilled water that is needed in certain applications; (2) the difficulty of economically balancing the type of fuel used for distilled water with the type of fuel used to generate hot water since, in some instances, a more expensive form of energy would be used for distilled water such as electricity than would normally be used to heat water in a household, which might be gas or even sunlight; and (3) condensers used for water cooled distillers may become fouled on the cooling water side by minerals in the cooling water, resulting in a decrease in heat exchange efficiency and possible restriction of the cooling water flow path.
The apparatuses in the prior art disclosures of combination hot water and pure water apparatuses have the disadvantage of not being economical for domestic use and being questionable for laboratory use. They are questionable for laboratory use, the purpose for which some of them are disclosed, because there is no relationship between the demand for hot water and distilled water that has been accommodated by the equipment.